The present invention relates to cylinder locks and, in particular, it concerns a cylinder lock apparatus that can be operated with or without a key.
In a conventional mechanical cylinder lock, when an appropriate matching key is inserted into the cylinder lock, the key serves to mechanically align tumbler pins, and thereby allowing the cylindrical plug to be rotated freely to open the lock. Referring now to FIGS. 1A and 1. B, which are representations of a prior art cylinder lock 10, with a key 12 inserted into the cylinder lock, and a door lock 15. Door lock 15 includes, inter alia, a shaped slot 16 for receiving cylinder lock 10 and a door lock bolt hole 17 through which a bolt (not shown) is inserted to secure the cylinder lock inside a door. Typically, door lock 15 is inserted into a hollowed-out edge of the door (not shown) and cylinder lock 10 is inserted through prepared holes in the door (not shown in the figure) and perpendicularly into and through shaped slot 16, substantially along axis 18. Door lock further comprises a locking tongue 19. Typically, cylinder lock 10, when unlocked, serves to translate locking tongue 19 allowing the tongue to alternately inhibit and allow opening of the door. Typically, other cylinder locks having a cross-sectional profile and length substantially matching cylinder lock 10 may be replaced or retrofitted instead of cylinder lock 10. Typical names/manufacturers of such cylinder locks include, but are not limited to: Euro Cylinders; Oval Cylinders; Asec 6-pin Euro profile; and Chubb M3. Overall lengths of such cylinders typically vary from approximately 70-95 mm.
Reference is now made to FIGS. 2A and 2B, which are cross sectional side views A-A of the cylinder lock shown in FIG. 1A. The cylinder lock has a body housing 20, which is bored from one end to the other end and a cylindrical plug 22, which is fitted into the bore, and which may be rotated, as described hereinbelow. A set hole 23 is located approximately in the middle of cylinder lock 10 to receive a bolt which is inserted into door lock bolt hole 17, to secure the cylinder lock within door lock 15, as described hereinabove in FIG. 1B. Cylindrical plug 22 has a key slot 25 formed axially in cylindrical plug. Key 12 is inserted into slot 25. A pin-tumbler set 30 is located in body housing 20 and in cylindrical plug 22 to serve to lock and unlock rotational movement of cylindrical plug 22. Cylindrical plug 22 and a second cylindrical plug 31 may be mechanically coupled and uncoupled to a rotating tongue 35 by means of a selector mechanism (not shown in the figure), which allows either cylindrical plugs to rotate the rotating tongue, which in turn serves to move the locking tongue of the door lock (refer to FIG. 1B). The cylinder lock shown in FIGS. 2A and 2B is called a “blind cylinder”, meaning that a key can be inserted into only one side of the lock, with only one pin-tumbler set present, and that the other side of lock cannot accept a key. However, cylinder lock 10 may also comprise pin-tumbler sets in respective cylindrical plugs at both ends.
FIG. 2B, which is a detailed view of FIG. 2A, shows in greater detail pin-tumbler set 30. Pin-tumbler set 30 includes tumbler pins 32 and driver pins 34, both of which are constrained to move generally perpendicularly to key 12. Springs 33 typically serve to preload the driver pins and the tumbler pins, displacing them towards slot 25, thereby advancing part of one or more of driver pins 34 into cylindrical plug 22 through openings in the plug (not shown in the figure) and thereby locking rotation of cylindrical plug 22 when no key is present in the slot. Typically, key 12 is formed to fit the pattern and respective lengths of tumbler pins 32. When key 12 is fully inserted into slot 25, the key presses tumbler pins 32 and driver pins 34 against springs 33, alignedly inserting driver pins 34 into body housing 20, and thereby enables rotation of the cylindrical plug. Whereas key 12 is shown inserted, with its wider traverse edge contacting the tumbler pins, another inserted orientation of key 12 may include its thinner traverse edge contacting the tumbler pins. Also, one or more additional sets of collinearly arranged tumbler pins (not shown) may be present, in the case of a master key, which is used to lock and unlock a number of such specially configured cylinder locks.
A number of prior art electronic or combination electrical/mechanical lock systems allow a user to open a locked cylinder in a number of ways. In U.S. Pat. No. 3,889,501 by Fort, whose disclosure is incorporated herein by reference, a combination electrical and mechanical system is described. The system includes a lock having a fixed lock cylinder and a rotatable key slug. A first solenoid is employed in the current system to drive a lock pin, which is normally extended to lock the key slug. Upon insertion of an appropriately aperture-encoded key, light sources and detectors mounted in the lock are used in concert with appropriate circuitry to operate to the first solenoid to unlock key slug. A second solenoid is operable, in response to an electrical power failure, to extend a latch pin. When the latch pin is extended a proper mechanical key is inserted and rotated, extension of the lock pin is prevented. A proper mechanical key can be inserted to move a plurality of spring loaded pin tumblers in the lock to enable rotation of the key slug during an electrical power failure.
Aston, in U.S. Pat. No. 5,839,305 whose disclosure is incorporated herein by reference, discloses an electrically operable cylinder lock device, which includes a body with a bore housing a rotatable barrel, having a key slot. The device has an electromagnet, which is employed to interact with a detent bar, the detent bar positioned to alternately inhibit or enable, with the aid of the electromagnet, rotation of the rotatable barrel. Another embodiment disclosed by Aston has a microswitch which interacts with an inserted key and controls the supply of electrical power.
While the prior art includes an array of combination electrical/mechanical lock systems of varying complexity, there is a need for an electronic or combination electrical/mechanical cylinder lock that, taking advantage of the inherent cylinder pin tumbler mechanism, can be unlocked or unlocked without the insertion of a key, while also functioning as a conventional lock operated with a key in case of an electrical power failure.